using Microsoft.Extensions.Options;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Nuuru.Server.Services
{
    public interface IIntegrityService
    {
        bool IsEnabled { get; }
        Task<IntegrityCheckResult?> VerifyTokenAsync(string token, string ipAddress, string action, string? userId = null);
        Task<bool> ReportErrorAsync(string error, string? ipAddress = null, string? userId = null);
    }

    public sealed class IntegrityCheckResult
    {
        public bool Valid { get; init; }
        public Guid? AssessmentId { get; init; }
        public string? BrowserHash { get; init; }
    }

    public class IntegrityService : IIntegrityService
    {
        private readonly HttpClient _httpClient;
        private readonly ILogger<IntegrityService> _logger;
        private readonly string? _apiUrl;
        private readonly string? _siteId;
        private readonly bool _isEnabled;

        public IntegrityService(
            HttpClient httpClient, 
            IConfiguration configuration,
            ILogger<IntegrityService> logger)
        {
            _httpClient = httpClient;
            _logger = logger;
            _apiUrl = configuration["Integrity:ApiUrl"];
            _siteId = configuration["Integrity:SiteId"];
            _isEnabled = !string.IsNullOrEmpty(_apiUrl);
        }

        public bool IsEnabled => _isEnabled;

        public async Task<IntegrityCheckResult?> VerifyTokenAsync(string token, string ipAddress, string action, string? userId = null)
        {
            if (!_isEnabled || string.IsNullOrEmpty(token)) return null;

            try
            {
                var requestBody = new Dictionary<string, string>
                {
                    { "action", action },
                    { "payload", token },
                    { "site_id", _siteId ?? string.Empty },
                    { "user_ip", ipAddress }
                };

                if (!string.IsNullOrEmpty(userId))
                {
                    requestBody["user_id"] = userId;
                }

                var response = await _httpClient.PostAsJsonAsync(_apiUrl + "/api/assessments", requestBody);

                if (!response.IsSuccessStatusCode)
                {
                    _logger.LogWarning("Integrity API returned non-success parsing token. Status: {status}", response.StatusCode);
                    return null;
                }

                var content = await response.Content.ReadFromJsonAsync<IntegrityApiResponse>();
                return new IntegrityCheckResult
                {
                    Valid = content?.Valid ?? false,
                    AssessmentId = content?.Id,
                    BrowserHash = content?.BrowserHash
                };
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Exception while verifying integrity token with external API");
                return null;
            }
        }
        
        private class IntegrityApiResponse
        {
            [JsonPropertyName("valid")]
            public bool Valid { get; set; }

            [JsonPropertyName("id")]
            public Guid? Id { get; set; }

            [JsonPropertyName("browser_hash")]
            public string? BrowserHash { get; set; }
        }

        public async Task<bool> ReportErrorAsync(string error, string? ipAddress = null, string? userId = null)
        {
            if (!_isEnabled || string.IsNullOrEmpty(error)) return false;

            try
            {
                var requestBody = new Dictionary<string, string>
                {
                    { "error", error },
                    { "site_id", _siteId ?? string.Empty }
                };

                if (!string.IsNullOrEmpty(ipAddress))
                {
                    requestBody["user_ip"] = ipAddress;
                }

                if (!string.IsNullOrEmpty(userId))
                {
                    requestBody["user_id"] = userId;
                }

                var response = await _httpClient.PostAsJsonAsync(_apiUrl + "/api/error-reports", requestBody);
                return response.IsSuccessStatusCode;
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Exception while reporting integrity error to external API");
                return false;
            }
        }
    }
}